Inventors:
Rickey J. Thomas - Lineboro MD, US
Florian Probst - Hutthurm, DE
Thomas J. Quinn - Towson MD, US
Abhijeet P. Joshi - Baltimore MD, US
Alfons K. Wetzl - Salzweg, DE
Albert Leidl - Passau, DE
David N. Johnson - North Bitchburn, GB
Assignee:
Black & Decker Inc. - Newark DE
International Classification:
B23B 51/02, B23B 35/00, B23B 27/14
US Classification:
408 1BD, 408230, 408144, 408199
Abstract:
A combination drill bit for use in both hand held drills and stationary drill presses has a shanking end, a working end and a helical flute portion between the shanking and working ends. The helical portion has a helix length (L) ofThe drill bit has a core that is tapered from the working end to the shanking end. A web thickness length at the working end is 10% to 35% of the diameter and the thickness length at the junction of the shanking end is 70% to 90% of the diameter. The drill bit is manufactured from a high speed steel including at least 5% by weight of cobalt.